* Faulty fuel pump: This is the most common reason. The pump itself may have failed.
* Fuel pump relay: A relay is an electrical switch that controls the pump; it might be faulty.
* Blown fuse: A blown fuse can also prevent the pump from working.
* Wiring problems: A short circuit or damaged wiring can interrupt the power to the pump.
* Low fuel level: Though less likely to completely stop the pump, an extremely low fuel level *could* cause issues.
To troubleshoot:
1. Check the fuel level: Make sure you actually have enough gas.
2. Check the fuses: Consult your owner's manual to locate the fuel pump fuse and check if it's blown. Replace if necessary.
3. Check the fuel pump relay: Again, consult your owner's manual to locate the relay and test it (you might need a multimeter for this).
4. Listen for the fuel pump: When you turn the ignition key to the "ON" position (but don't start the engine), you should hear a brief humming sound from the fuel pump. If you don't, the pump or its electrical supply is likely the problem.
If you've checked these and the problem persists, you'll need to take your Focus to a mechanic. They have the tools and expertise to diagnose and fix the problem, which likely involves replacing the fuel pump itself. Attempting to work on the fuel system without proper knowledge can be dangerous.
